This invention relates to an apparatus for and a method of identifying elements by using specified identification tables to compare data from a chromatogram obtained in gas or liquid chromatography.
FIG. 6 shows steps by which elements contained in a sample are identified in a prior art qualitative analysis. First, an analysis is carried out with a chromatograph to obtain a chromatogram which shows the concentrations of elements (relative intensity) eluted from a separation column as a function of time (Step S101). Peaks are detected by analyzing the chromatogram, from which data such as peak times and peak areas are obtained (Step S102). Next, each of the peak times in the analyzed data is compared with a preliminarily prepared identification table to identify the element corresponding to each peak (Step S103). This identification table is usually prepared by analyzing known materials and contains data such as components, retention times and peak shapes (areas and heights) corresponding to these components. In Step S103, each component is identified by determining the retention time in the table with which each peak time matches.
If the referenced table is inadequate, however, there may remain many unidentifiable components on the chromatogram or components with retention times to which no peak time will match. In such a situation (NO in Step S104), the identification table is either corrected or replaced by another (Step S106) and the step of peak identification (Step S103) is repeated. Only after it is concluded that a normal analysis has been done (YES in Step S104), the results such as the names of the identified components are outputted (Step S105).
By this prior art routine, Steps S103, S104 and S106 must be repeated as many times as necessary until an appropriate identification table can be set. In the analysis of a substance such as gasoline, containing hundreds of different components, each of which may be of different kinds, depending on the supplier, for example, it is extremely difficult to select an appropriate identification table. If it is necessary for the analyzer himself or herself to keep replacing the identification table and repeating the analyses, the qualitative analysis becomes both time consuming and labor consuming.